(a) Field of the Invention
The present invention relates to an integrated electronic power control unit sharing a DC input terminal of an environmentally friendly vehicle in which an inverter and an LDC (Low voltage DC-DC Converter), which are EPCUs (Electronic Power Control Units) in the environmentally-friendly vehicle, share a DC input terminal.
(b) Description of the Related Art
It is known to provide vehicles that are environmentally friendly, i.e., that have improved fuel efficiency, satisfy applicable governmental regulations, e.g., those of OBD (On Board Diagnosis) about exhaust gas, and which minimally use fossil fuels as a fuel source.
Such environmentally-friendly vehicles, including fuel cell vehicles, electric vehicles, plug-in electric vehicles, and hybrid vehicles, are equipped with one or more motors and an engine.
For example, environmentally-friendly vehicles may include a battery charged with power at high voltage for driving the motors, an inverter that is an electronic power control unit driving the motors by converting the DC high voltage of the battery into AC voltage, an LDC (Low voltage DC-DC Converter) that is also an electronic power control unit charging a low-voltage battery by converting DC high voltage into low DC voltage (for example, 12V), an engine clutch disposed between the engine and the motors to transmit power of the engine to a driving shaft, and various electronic power control units for controlling the operation of the environmentally-friendly vehicles.
Typically, environmentally-friendly vehicles can travel in an HEV (Hybrid Electric Vehicle) mode and an EV (Electric vehicle) mode by engaging or disengaging the engine clutch in accordance with the intention of acceleration/deceleration determined by the driver operating the acceleration pedal and the brake pedal, load, vehicle speed, and the SOC (State Of Charging) of the battery.
When an environmentally-friendly vehicle changes the traveling mode from the EV mode to the HEV mode, the engine clutch is engaged after the engine speed and the motor speed are synchronized so that torque does not change while power is transmitted between the engine and the motors, which utilize different power sources, thereby ensuring drivability.
Environmentally-friendly vehicles typically include an inverter and a low voltage DC-DC converter, as described above. The inverter and the low voltage DC-DC converter may be implemented, for example, by separate individual circuits, as shown in FIGS. 1 and 2, or an integrated circuit, as shown in FIG. 3.
FIG. 1 (RELATED ART) shows an example of the circuit configuration of the inverter, and FIG. 2 (RELATED ART) shows an example of the circuit configuration of the low voltage DC-DC converter.
FIG. 3 (RELATED ART) shows a circuit configuration obtained by simply integrating the inverter shown in FIG. 1 with the voltage DC-DC converter shown in FIG. 2.
The inverter can be called an MCU (Motor Control Unit) in the vehicle trade, because it is an electronic power control unit that drives a motor by converting DC high voltage into AC voltage.
Referring to FIG. 1, an inverter 10 is configured such that DC high voltage HV inputted to a DC input terminal passes through a capacitor module 12 composed of a plurality of capacitors, and the DC high voltage that has passed through the capacitor module 12 is converted into AC by a power conversion module 14, thereby driving a motor 20.
In the capacitor module 12 of the inverter 10, a DC capacitor 12a, which is a capacitor that levels input voltage, is generally a large-sized device, as apparent to those skilled in the art, and a Y capacitor 12b, a capacitor reducing noise in input voltage, is generally a small-sized device. Therefore, the capacitor module 12 of the inverter 10 is composed of the large-sized DC capacitor 12a and the small-sized Y capacitor 12b. 
Referring to FIG. 2, the low voltage DC-DC converter 30 is configured such that DC high voltage HV passes a choke coil 31, a Y capacitor 32b, and an X capacitor 32c, and is converted across a plurality of various devices including a plurality of MOSFETs 33, a coil, a transformer, an inductor, a diode, and a capacitor, and then outputted.
The Y capacitor 32b and the X capacitor 32c included in the low voltage DC-DC converter 30, which are capacitors for removing noise in input voltage, are generally small-sized devices.
Referring to FIGS. 1 to 3, it can be seen that an inverter and a low voltage DC-DC converter according to the related art are separate individual electronic power control units or integrated simply in one package, such that they do not share a DC voltage input terminal.
Therefore, the inverter and the low voltage DC-DC converter according to an embodiment of the related art have the problem in that they decrease spatial availability in environmentally-friendly vehicles and increase the manufacturing cost.
The Description of the Related Art is made to help understanding the background of the present invention and may include matters out of the related art known to those skilled in the art.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.